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Securities - Amortized Cost and Fair Value, Available for Sale (Details) - USD ($) $ in Thousands | Dec. 31, 2018 | Dec. 31, 2017
--- | --- | ---
Cash and Cash Equivalents [Line Items] |  |
Amortized Cost | $ 1,264,529 | $ 674,104
Gross Unrealized Gains | 4,517 | 7,872
Gross Unrealized Losses | (18,269) | (10,488)
Fair Value | 1,250,777 | 671,488
Trust preferred securities |  |
Cash and Cash Equivalents [Line Items] |  |
Amortized Cost | 12,359 | 12,442
Gross Unrealized Gains | 0 | 0
Gross Unrealized Losses | (1,726) | (3,054)
Fair Value | 10,633 | 9,388
Other debt securities |  |
Cash and Cash Equivalents [Line Items] |  |
Amortized Cost | 44,046 | 17,106
Gross Unrealized Gains | 192 | 260
Gross Unrealized Losses | (311) | (76)
Fair Value | 43,927 | 17,290
Obligations of other U.S. Government agencies and corporations |  |
Cash and Cash Equivalents [Line Items] |  |
Amortized Cost | 2,536 | 3,554
Gross Unrealized Gains | 13 | 40
Gross Unrealized Losses | (38) | (30)
Fair Value | 2,511 | 3,564
Obligations of states and political subdivisions |  |
Cash and Cash Equivalents [Line Items] |  |
Amortized Cost | 200,798 | 228,589
Gross Unrealized Gains | 3,038 | 6,161
Gross Unrealized Losses | (567) | (269)
Fair Value | 203,269 | 234,481
Government agency mortgage backed securities | Residential mortgage backed securities |  |
Cash and Cash Equivalents [Line Items] |  |
Amortized Cost | 621,690 | 196,121
Gross Unrealized Gains | 719 | 888
Gross Unrealized Losses | (9,126) | (3,059)
Fair Value | 613,283 | 193,950
Government agency mortgage backed securities | Commercial mortgage backed securities |  |
Cash and Cash Equivalents [Line Items] |  |
Amortized Cost | 21,957 | 31,015
Gross Unrealized Gains | 257 | 389
Gross Unrealized Losses | (384) | (234)
Fair Value | 21,830 | 31,170
Government agency collateralized mortgage obligations | Residential mortgage backed securities |  |
Cash and Cash Equivalents [Line Items] |  |
Amortized Cost | 332,697 | 180,258
Gross Unrealized Gains | 274 | 133
Gross Unrealized Losses | (5,982) | (3,752)
Fair Value | 326,989 | 176,639
Government agency collateralized mortgage obligations | Commercial mortgage backed securities |  |
Cash and Cash Equivalents [Line Items] |  |
Amortized Cost | 28,446 | 5,019
Gross Unrealized Gains | 24 | 1
Gross Unrealized Losses | (135) | (14)
Fair Value | $ 28,335 | $ 5,006

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- Definition Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale). + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27161-111563 + Details
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